Various types of blocks adaptable to surfaces such as the surface of a truck or railway car for used transporting road vehicles already exist.
One such device is described in French Patent No. 2.725.946 filed by the applicant.
The block described in this patent comprises a locking support base which can be immobilized inside perforations on the carrying surface, and a block structure attached to the support base which pivots between two positions: a flattened position parallel to the carrying surface allowing passage of the vehicles, and an upright position perpendicular to the carrying surface for immobilizing the vehicles. The plate-like support block has two immobilizing claws on its lower surface anchoring it to the carrying surface. Said immobilizing claws, designed to interlock separately within a perforation on the carrying surface, are rotated simultaneously like a rotary lock to alternate between a position for extracting them from the perforations and a locked position, in which the block is immobilized on the carrying surface of the transport vehicle.
Another such block is described in French Patent No. 2,684,054 filed by Officina Meccanica di Migliore Livio. It consists of two cross-pieces transverse to the carrying surface which support the wheel of the vehicle to be immobilized, and two blocking fingers to immobilize it on the carrying surface. One of these fingers pivots between an unlocking position, in which it penetrates or is extracted from a perforation in the carrying surface, and a locking position rotated 90.degree. from the unlocking position, when it is locked in the perforation. The other locking finger is attached opposite the first, separated from it by the same interval that separates two perforations, and it is fixed.
Yet another block is described in European Patent No. 0710,584 in the name of Societe Kassbohrer. This block consists of a transverse stop with lateral returns which is a single unit formed from a tubular element. It also comprises two immobilizing fingers to anchor it on the carrying surface, one consisting of a pivoting hook and the other being fixed.
The prior art blocks described briefly above each have at their extremities at least one immobilizing finger or claw anchoring them to the carrying surface. Depending upon the execution, either or both of these claws may pivot between a position which unlocks the block, when they are parallel to the longitudinal axis of an opening in the perforated carrying surface, and a locking position, when they are blocked inside the perforations. This technical solution has been devised to ensure that the block, and thus the vehicle being transported on the carrying surface of the transport means, remains firmly in place.
Nevertheless, the prior art solution of providing two end locking fingers poses several problems.
Positioning and extracting the blocks are difficult operations. In practice, when the block is placed on the carrying surface, each locking finger must be positioned to coincide with the opening of a perforation on the surface. This operation, performed manually, is difficult for the user, as this type of block is very heavy and there is no access to the lock located on the interior of the loading surface, that is, on the surface bearing the vehicle to be transported. On the other hand, when extracting the block, the locking fingers frequently remain locked inside the perforations. Extraction becomes even more difficult when the vehicle wheel is blocked against the stop structure on the block. Furthermore, these prior art blocks are expensive due to high manufacturing costs.